Which of the following is a correct statement:

Question

$\begin{array}{1 1} a. Na_2S \;is\; sodium \;sulphide, Na_2SO_3\; is\; sodium \;sulphite, Na_2SO_4 is \;sodium \;sulphate \\ b. Na_2S \;is \;sodium\; sulphite, Na_2SO_3\; is\; sodium \;sulphide, Na_2SO_4 \;is\; sodium\; sulphate \\ c. Na_2S \;is\; sodium \;sulphide, Na_2SO_3\; is\; sodium\; sulphate, \;Na_2SO_4\; is\; sodium\; sulphite \\ d. Na_2S \;is\; sodium\; sulphite,\; Na_2SO_3\; is\; sodium \;sulphite, Na_2SO_4\; is \;sodium \;sulphide \end{array}$